Base plate for mortars



June 26, 1951 w. R. GERHARDT 2,557,960

BASE PLATE FOR MORTARS Filed April 15, 1. 946 3 Sheets-Sheet 1 I I H II I W IH! 26 Il W1 1 11am R E Erhardt y wvwiia June 26, 1951 w. R. GERHARDT 2,557,960

BASE PLATE FOR MORTARS Filed April 15, 1946 3 Sheets-Sheet 2 William R B Erhar dt June 26, 1951 w. R. GERHARDT BASE PLATE FOR MORTARS 3 Sheets-Sheet 5 Filed Apri 15, 1946 Patented June 26, 1951 BA'S'E PLATE FOR :MORT-ARS William R. GerhardtQWatertown Arsenal, Mass, ass gnor to the United States of America as represented ;by the Secretary of War APmicafiQn April 15, 1946, SerialNo. 662,157

(:Granted under the act of March 3, 1883, as

amended .April 30, 1928; 370 G. '757) 4 Claims.

The invention described herein may be manufactured and used by or for the Government for government purposes, without the payment to me of any royalty'thereon.

This invention relates to ground-engaging devices for supporting weapons, suchas base plates for mortars.

"Heretofore, such base plates have been fabricated in one piece and, to withstand firing stresses, of heavy construction. As a result, the base plate was too large and unwieldy for port ability .by the average member of a gun crew. This is undesirable, particularly in combat, as it often becomes necessary to .disassemble the gun equipment as rapidly as possible preparatory to establishing a new gun site. Apurpose of my invention is to provide a-base plate that can be madeas large and heavy as is necessary to form the proper base support for a gun and yet be so constructed that it may be disassembled into its component parts each of which can be easily handled by a member of the gun crew. It was found that in actual practice the weight of each component part should not exceed '70 lbs., this Weight being the average amount that could be "conveniently handled by an individual.

Another purpose :is to provide a base support in which thecomponent parts can be easily and rapidly assembled and disassembled without the aid of special tools.

tion will be apparent from the following description and accompanying drawings in which:

Figure 1 is a plan view of the assembled base plate.

Figure .2 is an-exploded view of the base plate with the component rings thereof in section through 22 of Figure .1.

Figure 3 is a plan view of amodified form of base plate.

Figure 4 is an exploded view of the modified base plate with the component rings thereof in section through 4.4 of Figure '3.

Figure "5 is a cross-sectional view of an additional form of a'baseplate.

Figure 6 is a perspective view of the assembled base plate supporting a mortar.

Figure 7 is a plan View of theball clamp and the locking knob -for retaining the breech end of a mortar on the base plate.

Figure 8 is a section-tthroughJ-j oirFigure'i'l 2 showing details of socket for receiving ball-like member on breech end of a mortar.

Figure 9 is a plan view of the ball clamp.

Figure 10 is'a section through Ill-l0 of Figure 9.

Figure 11 is a plan view of the locking knob.

Figure 12 is a side view of the locking knob with a portion thereof in section taken through lZ-iZ of Figure 11.

Figure 13 is a bottom view of locking knob.

Figure 14 is a section through i l- M of Figure 1, showing details of one form of a latching device.

Figure 15 is a plan view showing a modified form of a latching device.

Figure 16 is a plan view of another form of a latching device.

As generally shown in Figure 6, 'the' base plate is adapted to support the breech end I of a 15'5-mm. mortar or similar weapon, the bore end of which may be mounted'in the usual bipod assembly as is well knownin the art.

The base plate as shown in Figures 1 and 2, consists of a central plate and of a number of overlapping concentric angular rings: An outer ring 2, a central plate 3 and an inner ring 4. The number of annular rings as well as their :individual shapes may be varied to obtain the desired bearing area 'for'the particular size of mortar to be supported; for instance further concentric rings of increasing diametrical dimensions may be added to provide more than two concentric rings as shown in the specific embodiment'illustrated in Figs. 1 and 2 of the drawing.

A "latching means .5, to be described further, lock the rings together into a unitary support that can be broken down for convenient trans port,

The central plate 3 as shown inF'igure '2 has a fiat inclined top surface terminating in -a depending peripheral flange f3" and is also provided with an opening receiving a socket '6 having an outer flange '1 provided with threaded bolt :holes for receiving a pivot bolt 8 and a locking bolt"9. The breech end I of the mortar has a ball-dike member 1" adapted to be received in the socket 6. A ball clamp H! in the form of a curved plate is provided with a handle extension I0 andis pivoted at one end on'the bolt 8. The inner periphcry of the ball clamp 10 is rounded at H for engaging the ball-like member to lock it in the socket 6. The other end of the ball clamp 10 has a notch formed by the aperture l2 andithe slot 1:3 for the reception of a locking knob 15.. The locking knob :15, as shown. in Figure-.18 is rotatable about the bolt 9 and, as shown in Figures 11, 12 and 13, has a knurled cylindrical portion I6 having a fiat side l1, a recess l8 receiving a spring [9, and a depending cylindrical portion 20 having oppositely fiat sides 2|. The portion 20 is adapted to be received by the aperture I2 when the flat sides 2| are parallel to the sides of the ball clamp slot l3.

A rotation of substantially 90 degrees will cause the knob l5 to assume the position shown in Figure 7 to lock the ball clamp against the ball-like member of the breech end of the mortar. The flat side 11 on the knurled locking knob I is merely to indicate to the operator Whether the knob is in locking or unlocking position. When the fiat side I1 is in the position shown in Figure 7, the operator is aware that the ball clamp is locked against the ball-like element of the mortar. The spring l9 forces the depending portion 20 against the socket 6 to frictionally prevent accidental unlocking of the clamp l3. This ball and socket arrangement permits the mortar to be adjusted as desired for firing.

The socket 6 may be formed integral with the inner ring or, as shown, may be a separately fabricated part welded or otherwise fastened to the inner ring. -An inner ring 4, as shown in Figure 2, has a fiat top face with the same angle of inclination as the central plate surface forming in effect a continuation thereof, and is provided with an outer peripheral flange 22 and depending inner flange 23. An annular flat ring 24 is secured to the inner flange 23. The peripheral flange 3 of the central plate 3 has a sliding fit within the flange 23 and rests on the annular flat ring 24. Thus, the central plate 3 is supported by the intermediate ring 4.

An outer ring 2, as shown in Figure 2, is constructed, except for size, similar to the intermediate ring 4. Additional rings when required would be similarly constructed. Each concentric ring 2 and 4 has an outer edge 22' and an inner edge 23.

Each concentric ring 2, and 4 as well as central plate 3 is equipped with a pair of oppositelyspaced handles 25 and on its underside with spade elements. The spade elements, attached to the inner ring 4 and outer ring 2 are formed from a series of substantially truncated triangular plates 26 at right angles to a series of radial plates 21, the latter being stepped to receive the depending inner flange and annular flat ring of each concentric ring. The triangular and radial plates are paired and welded or otherwise secured to each other and to their respective ring. The spade elements on the central plate 3 are formed from depending plates 28 bridging the socket member 6 and radial side plates 29. The spade elements decrease in length from the center of the base plate.

It is obvious that the shape and size of the depending flanges and the spade elements may be altered without affecting my invention. For example, as shown in Figures 3 and 4, the central annular plate 42 may be provided with a depending conical portion 43, ribs 44 and plates 45. In lieu of stepped radial plates 21 of Figure 2, truncated rectangular plates 46 may be employed between the flanges 41 and 48, with the flange 41 carrying the annular flat ring 49 reinforced by triangular plates 50.

In a further modification shown in Figure 5, the depending annular flanges 41' and. 48 are extended and held against buckling by radial plates 46' and the central annular plate 42' is provided with an annular skirt 44' suitably reinforced by radial plates.

The various rings, flanges and plates may be provided with flanged openings 52 for decreasing the weight of such parts and the top surfaces of these rings may be flat, as shown, or may be curved to form a concave surface. The inclination or concavity of the base plate top surfaces as well as the length of the spade elements permit the base plate to present a firm support with which to effectively absorb the recoil of the gun at the various firing angles to which it may be adjusted.

With the exception of the central plate, the rings are equipped with latching devices 5. Although I have shown three of such devices distributed about the rings, a greater or lesser number may be employed.

Each latching bar, as shown in detail in Figure 14, is pivoted about a bolt 30 secured to the rings and is provided at one end with an extension 3|, a groove 32 on its underside containing a spring 33 for forcing a friction plate 34 against the annular ring top surface, and a free end 35 adapted to overhand its annular ring and frictionally engage the surface of the adjacent inner annular ring top or central plate surface to force the depending peripheral flange of the latter against annular flat ring of the next outer ring. The spring-pressed plate 34 functions as a friction-lock to retain the latch bar in position about its pivot bolt 30. Thus, the latching bars 5 force an outer annular ring into contact with an adjacent inner annular ring and an inner annular ring into contact with a central plate whereby all these rings and central plates are rigidly connected together as a unitary unit.

A stud 36 limits rotation of the latching bars about the pivot bolt 30, to a substantially radial position. It thus prevents an operator, particularly under conditions of combat, blackout, etc., from moving the latching bar beyond its proper locking position. In the modification shown in Figure 15, a bolt 31 is utilized both as a stop and a locking device by screwing its head down against the latching bar which has a notch 31' for receiving the shank of the bolt 31. In an additional embodiment shown in Figure 16, one latching bar is employed to simultaneously lock together three annular rings. The latching bar 38 is pivoted about the bolt 39 and is sufiiciently long to frictionally contact the inner annular ring top surface and engage the underside of a lip 40 carried by the outer annular ring 2. An extension similar to 3| of Figure 14 may be at tached to each latching bar 38 to assist in the manual operation of the same. When deemed to be desirable, additional studs 36' and bosses 5l may be employed as illustrated in Figure 3.

The ball clamp and the latching ,bars may be forced into or out of locking position by employing against the extensions l3 and 2 I respectively, any means .thatmay be convenient to operator at the time, such as the operators hand or foot, or any tool or large rock, etc.

, It is obvious that the annular rings of the base plate may be formed by casting, welding or bolting of the various parts.

It will be apparent that in addition to the various modifications disclosed above, others may be made, without departing from the spirit and scope of my invention asset forth in the description, drawings and claims.

i claim:

1. A base plate for a gun comprising a plurality of unitary concentric ground engaging rings each having an outer edge and an inner edge which define the ring, the outer edge of each ring being shaped to interfit snugly with the inner edge of an adjacent ring, each ring having a flange on the outer edge and an annular flat ring secured to the inner edge, the annular flat ring of each ring having a diametrical dimension equal to the diametrical dimension of the flange of an adjacent ring, the outer edge of each ring overlapping the inner edge of its adjacent ring Whereby a downward force on the innermost ring is transmitted to all adjacent concentric rings.

2. The invention according to claim 1 wherein the annular flat rings and flanges are so faced that each ring can be dropped into fitting position with its next adjacent ring of larger diametrical dimension.

3. The invention according to claim 2, including a central plate dimensioned to interfit with the inner edge of the innermost of said concentric rings, said central plate and innermost ring having cooperating flange and annular flat ring means at their adjacent edges constructed to transmit a downward force on said central plate to said adjacent ring, and means on said central plate for supporting the breech end of the gun.

4. The invention according to claim 3, including spade elements attached to the bottom of the ground-engaging rings, said spade elements decreasing in size with ground-engaging rings of increasing, diametrical dimensions.

WILLIAM R. GERI-IARDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 150,024 Goddard Apr. 21, 1874 1,730,800 Brant Oct. 8, 1929' 2,046,518 Joyce July 7, 1936 2,182,010 Brandt Dec, 5, 1939 2,264,791 Fries Dec. 2, 1941 2,383,087 Shaffer Aug. 11, 1941 2,425,783 Buquor Aug. 19, 1947 FOREIGN PATENTS Number Country Date 104,525 Great Britain Feb. 28, 1917 308,479 Germany Sept. 11, 1917 298,910 Germany May 15, 1920 331,115 Germany Dec. 31, 1920 570,613 France Sept. 3, 1923 816,093 France Apr. 6, 1936 147,252 Austria Oct. 10, 1936 494,355 Great Britain Oct. 25, 1938 61,990 Norway Jan. 29. 1940 

